PHILADELPHIA (CBS) — For the first time in US history, there are more adults living with congenital heart defects than children. Advances in modern medicine have allowed children who in years past would have died to survive and thrive.

It’s called the Philadelphia Adult Congenital Heart Center. Medical director Dr. Yuli Kim (right) says, “There is a real vulnerable time period — adolescents are learning to gain independence and going off to college, and this is certainly a time period that we know in the research that patients with congenital heart disease get lost to care.”